Isomerization of unsaturated nitriles



pounds Patented Sept. 11, 1945 UNITED STATES 584,630 rsomrzs-rrou or overruns-rm) m'rnnliis John E.

Phlllhl Delnwnre 7 Claims.

This invention relates to the catalytic isomeriilltlon of unsaturated nitriles. that is. nitriles oi urns-unrated acids. in which said isomerizaton involves a shift in the position oi an oleiinic linklI-Ee riioieflns are described.

tlon in such processes involves 1.4 addition of hydrolen cyanide to the conlueeted system. re-

sultinl in the production oirbetagamme-unsaturated nitriles- (2-alkenyi cyanidesl. Although valuable in themselves as interphabeto isomers valuab e. especially when the unsaturated nitriles are to be employed in the manufacture of synthetlcresins and rubber.

For the purpose or convenience. the unsaturated nitriles to which the present invention is articu- Iarix directed will be referred to as alkenyi cyenides. although reference to them as nitriles oi thescldtowhichtheycanbehydroiyzedisthe p erred nomenclature. Typical unsaturated nitriles. to which the isomerizetion process of the present invention is particularly adapted, when referred to es cyanides, are: Z-propenyl eyanlde (Gila-:CH-OHa-C. allyl cyanide, 3-hutenenitrile. cyono-fl-propenevinyiecetonitriie), 1- cyonide (CHi-CH=OHCN. crotcnitrile', 2-butenenitrile waned-propane). 2-hotemrl cyanide (CI-b-CH=CH-CI-Ie-CN, sentenenitriie. eye-no 2-butene. propenylacetonitrile), l-butenyl cyanide l-pentenenitrile. cyano-l-butene). and fl-cyclor tenyl cyan In general. the commeybe referred to as alkenyl eyanides and include both aliphatic as well as cyclocllphatic un- Mshan. Bartlesrme, Okla... sssignor Petroleum Gomosnr, a corporation of More Specifically,

Application Me! is, it, eriaI No. 535,546

saturated nitriles. It is to he noted that, in reion-in: to thecompormda as aikenyl cyenides or cyenoalkenos, the unsaturotion is desiznlted by a diiierentnumberthanisusedinrei'errlnztothem as ulkenenitriles.

Iiris an object or the present invention to providea rocessiortheisoinerizationotz-aikenyl cyanldes to the cormspondin: i-slkem'l cyunides.

Another oblect of this invention is to provide it! eflicient contact catalysts {or isomerization.

A further object is to convert Z-alhcnyl cya'nides to i-eikenyl cyanides under vapor-phase conditions over solid alkali and rth motel it cyonidesos catalysts. i

laboratory methods for eiieetlnl the shift of of unsaturated nihlles have been aciivetinl oltelm has been an aqueous aiirali solution used under liquid- 20 phase reaction conditions. However, such methods have certain well-defined limitations. Thus, it has been reported that 24 hours are required to establish equilibrium conditions at moderate temperetures whereas. at elevated .soas poniiication oi the nitrile becomes a serious factor. Thus. employment of aqueous alkaline estaiysts under operative conditions is economically unattractive because of tain solid contact ca at hereiuaiter. The is accom vaporizing the unsaturated nitrlle and preheotinr it to the desired reaction temper ture. The nitriie vapors are then over the solid catalyst at a rate such that equilibrium between the m 40 isomers is established. The eiliuent is passed throush a condenser and the product isthen subsubsequent fractionation, where feasible.

The uncon- 45 with fresh teed to the isomer-incision catalytic none.

In some instances. the boilin:

ew tlon'slwvery o! the 86 such mixtures of isomers are utilized.

electing the said 2 maouao meatamteiorueeiniheproceseoflhepreoieotedwithintheranze ilwruimooeiym'to eat invention comm-he such materials a \lkeii wimmmltelr 1000' l". (mm'oximotei; 200' to and olhiino-eorth motel cnnidee. More lpewnmtimlteiy'flo 6.). with cifleeiiy. the cnnides of sodium, potassium. oeitweenopproximebeiy 500' end opprouimoteiy meium. strontium and box-iumhflfe een ioundiobe 6 1". (mmximoteiy 250 and lmroximetely 815 poi-ileum]: memi e; ooh-11m; in the present b ine mien-ed. ilolherinflon reaction. Beeeuee oi their hixher In order to meintein vapor-phase eventing melting points, aiiniine-eorth mete! cyanide; no conditi n. 11mins rennin: mm mmsomew'hot preferable to oihli meiei ennidee. I Pherie to low luoenhnosnherieweauxes u-e emiu've round that the moat eiieotlve cab-Into are 10 Wed. In the use of unsaturated nitriiee luv. thooe eomorilipo o eeieetedennide suspended on in: six or more corhonotom; per molecule, ateooiidldeorbehteln-ier. Thea-id ocisorbentoorm rit: to lubltmoephu-io pm o pm. rienmdbemohmeteriehuoetivotedoher iorl'edinm'dertominimimtion re. ooei. Mien-f: eerth. bauxite. silica eel m4 theiiko. l-ctiom- In the use 01' the lovely nitriiee. preo- Apriefl edmethodofclhl'ntmmtloncomis some in excess or about :5 pound; per ounce prises em'yin: the odsorbeni earner meieriil inch use erenot ordinarily delirebie. In men: with in iqueoua eoluiion oi the cnnide followed instances. the use or m inert diluent is Minnby daring to move water. By enemieoppiioe- News. iionoiiiieeyuiideooiutiontothe eorrienmeierlei The now rite of minute: nitriie to the and evaporation e: umthezeirom. desired com 20 ieomeriation oohint is renamed so as to result eenirotioneolooiideanideemaybeepoiledto ine'eeotionoroonteeeperiodoin-omopmnihe-oenier. The finished mum. however. mun mainly 1 to lmilmrimoteir 20 mm, with the be rendered Iuboemtloiir anhydrous prior to tile preferred rouge being m pm. lathe bowel-notion reeoiion. ll!!! mmlimoioiy i0 oeeome,

-'ihez-aitenyiennideewhiehmoybeueodinzo lliefollolinlonmpieowflleemtomm fie prooeoe-o! thh invention, in :eneni. comprise memo processes the thopepreoo'rodhqthedireetodditionothrdmgen in fobeundenoood flat they donotrepreaeni; mnido to oonI'IlI-ie dioiefins. However. it is oblimitation: or the invention.

Hone tint similar oompoimiio from other sources mm 1 (to: male. il-pxopenzi mam) maybe ieomin exiled ih loourdmoe with the peoeeu. 'rhepmll?! We m-nropenoi mice) we; mm eat invention}: portiouiuiy directed to unutu- In presence of e. barium cyanide cow to 'roieii nitrileojrom the eliphztie and olieyeue l velubotenem ilomei'lhflmboi-m'bnem lmm u u u t m M ..u m Dido (emiionih-iie). 'lhocltalnt m: ap- V derivatives. lpoeiiieenmpiuoil-flkennen- 5olllieroenhbywoilhtoiboriummm leyonideJ-hutenylmuide. mum-minimum (0 I-penteoyi ennide. i-meihyi-z-butenyi cyanide. to 14-well: aim) and m 1 i in e the:

ma-bum mum. SJ-dImetbyL-Q- who ii w mr one. The

m guide. I-orelopeniaen maids. 2-

and oi these (0 3! yanide: added drop-wine chum eyonide both u m u. thovertiooltuboatenteotlwroximlteiyi plutio, Aiihmhihe eonvenion oi i-eikenri or onideetoi-flhemionoideeienomalirthede- --liredreei:iioliritioobviouethottheprooeuoi Aihrmoaofomlmnideimibemtreoiaed,

n; invention io-miiclbio without whet-Mini is the e men muhieuwithmmmem Motion to the reveree :eoeiion. namely. flmhi-mmi ieomeriaiion ot 1-eikenri ennides to I-olhenyi m mbmiibueaon the mnides.

*Reoetion tempenmru are leioeted eomeet the he WM iii-h mam m of m. u alo indieotedaoouveraionoiflmeont otthe eiiyl .mu-ueeemmaemginebemm The m eioi-memiennue. meticulouomentilomerintionreoetiouhnbeentoundto p homduotwnilmedtheoonoiuoim beer-m e, I

type. mean-u. M abmfineemum.

' V eyepiece-to l-oikenyl cyanide; Eovevenin oomlquoouo sodium mnide ooiutioa onto mnuiu mereioi mention, a. temperature nlmcientiy eie activated charcoal (0 to 14-inch line) and dry- -.vaiedtoteeuit-innneennomieolreeetionnoe iugthoontliysintflivtomlfii'ozlelenl ,iniIsthe-loie'oteihmoe mammal; opposing home. 'medweehlxetmdbnoeedinlrnex Der howioaiveooonfieoi'timeoi' condensed efliuent indieetedoeouvenionoifioln oeee'n eeniw 5 mounds. 'hqueni bromine Hm asaasso mine titration, 158 cc. of total eilluent was frac- Equilibrium concentrations of 2- and 3-pentenenitriles were realised. This was confirmed b subjecting pure a-pentenenitrile to the same treatment at 5'15 to 600 F. Several passes through the catalyst tube resulted in a constant Z-pentenenitrile concentration oi 12.4 per cent.

Example 3 A catalyst comprising 12 per cent by weight of potassium cyanide supported on iuiier's earth was prepared according to the method described in Example 1, and was subsequently used in the conversion oi z-cyclopentenyl cyanide to l-cyclopentenyl cyanide. The liquid nitrile feed was added at a rate 150 liquid cc. per hour together with a stream of nitrogen gas equivalent to approximately liters per hour (N'I'P). The reaction temperature was maintained at 500 to 525 F. throughout the run. Bromine titration of the total eiiiuent indicated a conversion to 1- cyclopentenyl cyanide of 58-60 per cent per pass.

While I have described my invention in detail with the inclusion of certain specific embodiments, no limitations are intended except as delined in the claims.

I claim:

1. A process tor the isomerization 01' a z-alkenyl cyanide to a i-alkenyl cyanide which comprises contacting the 2-alkenyi cyanide in the vapor phase with a solid catalyst comprising a substance selected from the group consisting 01' alkali and alkaline-earth metal cyanides at a temperature within the range of approximately 400 to approximately 1000 F.

2. A process as defined in claim 1 in which the contact time is within the range of approximately 1 to approximately 20 seconds.

3. A process for the isomerlzation of allyl cyanide to crotonitrile which comprises passing allyl cyanide in the vapor phase at a temperature within the range 0! approximately 400 to approximately 450' 1'. over a solid catalyst comprising barium cyanide.

4. A process for the isomerization of il-butenyl cyanide to i-butenyi cyanide which comprises passing z-butenyl cyanide in the vapor phase at a temperature within the range of approximately 5'15 to approximately 600" F. over a solid catalyst comprising sodium cyanide.

5. A process tor the isomerization of z-cyclopentenyl cyanide to l-cyclopentenyl cyanide in the vapor phase which comprises passing z-cyclopentenyl cyanide at a temperature within the range of approximately 500 to 525 C. over a solid catalyst comprising potassium cyanide.

6. A process for the isomerlzation oi a 2-alkenyl cyanide to a i-alkenyl cyanide which comprises contacting the 2-alkeny1 cyanide in the vapor phase at a temperature within the range of approximately 400 to approximately 1000 F. with a solid anhydrous catalyst comprising a substance seiected from the group consisting 0! alkali and alkaline-earth metal cyanides supported on a solid adsorbent carrier.

7. A process for the isomerlzation of 2-butenyl cyanide to l-butenyl cyanide which comprises passing 2-butenyl cyanide in the vapor phase at a temperature within the range of approximately 575 to approximately 600 F. over a solid anhydrous catalyst comprising sodium cyanide supported on granular activated charcoal.

JOHN E. W. 

